The present invention relates to an athletic shoe sole design and construction, and more particularly, to a sole assembly having a vent or a vent hole formed in a midsole.
The sole of an athletic shoe is generally comprised of a midsole and an outsole. The midsole is typically formed of soft elastic material in order to ensure adequate cushioning properties. The outsole is fitted under the midsole and directly contacts with the ground.
Preferably, ventilation of a shoe is secured in a degree when wearing a shoe. Various kinds of shoes with vent holes have conventionally been proposed.
For instance, the Japanese patent application laying open publication No. 8-131204 discloses a plurality of transverse holes formed at a body portion of the bottom member of a shoe and a plurality of vertical holes also formed at a body portion of the bottom member. The vertical holes communicate with the transverse holes and penetrate through the insole. The Japanese utility model application examined publication No. 63-43923 shows a plurality of through holes penetrating through the upper member of a sole in the thickness direction and a plurality of grooves formed at the lower member of the shoe. Each of the grooves corresponds to each of the through holes.
In both cases, the air flows into a shoe through the transverse holes and the vertical holes, or the through holes and the grooves. Thus, ventilation of the inside of a shoe is acquired.
On the other hand, in an athletic shoe, especially in the case of a running shoe, higher flexibility of the forefoot portion is required. In the prior art construction, however, transverse holes or grooves are merely formed on the body portion or the lower member made of rubber or the like. Thus, these transverse holes and grooves, which are made only in the light of ventilation, cannot satisfy higher flexibility that are required in an athletic shoe.
The object of the present invention is to provide a sole assembly for an athletic shoe that can realize higher flexibility as well as ventilation of the forefoot portion of a shoe.
The present invention provides a sole assembly for an athletic shoe.
In one embodiment, a sole assembly comprises a midsole extending from the heel portion to the forefoot portion, a curved or bent groove formed on the bottom side of the forefoot portion of the midsole and extending in the general shoe width direction, a through hole that is open on the plantar contact face of the midsole and formed in the curved groove, and a cover portion that covers the curved groove. The curved groove and the cover portion form an air tube.
The air tube may be open at one end or at both ends. An openable and closable valve means may be provided at the opening portion of the air tube. The valve means may be formed of a projection or a protrusion at the bottom portion of the curved groove in the vicinity of the opening portion.
Alternatively, the air tube may be closed at its both ends and an open air intake port communicating with the through hole in the curved groove may be formed at either the midfoot portion or the heel portion of the midsole. Also, the cover portion may be formed integrally with an outsole disposed on the bottom side of the forefoot portion of the midsole.
In use of a shoe, the air is introduced or flows into the inside of the shoe through the curved groove and the through hole, and thus, ventilation can be acquired inside the forefoot portion of the shoe. Moreover, in this case, the thickness of the midsole is smaller at the curved groove formed portion, which causes the midsole to be easier to bend in the vertical direction along the curved groove, thereby improving flexibility or bendability of the forefoot portion. This improved flexibility can realize smoother transfer of the load and secure gripping properties when an athlete or a shoe wearer gets down onto the ground from the heel portion to the toe portion of the shoe.
Furthermore, the opening portion of the through hole on the bottom side is prevented from being exposed to the ground by the cover portion. Thereby, water, sand, dust, and the like outside the shoe are blocked from entering the inside of the shoe via the through hole when the shoe contacts with the ground. In such a way, the shoe can be used as an outdoor shoe as well.
When at least one end of the air tube is open, the open air is introduced into the curved groove through the opening end of the air tube and flows into the inside of the shoe via the through hole from the curved groove.
When the openable and closable valve means is provided, the valve means closes the opening portion of the air tube at the time of bending of the forefoot portion, thereby increasing the air pressure inside the air tube. The pressure increased air in the air tube easily flows into the inside of the shoe via the through hole, which improves ventilation of the shoe.
When a projection or protrusion is provided in the curved groove, it contacts with the cover portion at the time of bending of the forefoot portion, thereby closing the opening portion of the air tube. In this case, because the valve means is formed of a mere projection or protrusion, the structure of the valve means can be simplified.
When both ends of the air tube are closed, the air pressure inside the air tube easily increases at the time of bending of the forefoot portion and the pressure increased air is pushed out of the through hole and flows into the inside of the shoe. In this case, the open air is introduced into the air tube through the intake port formed at the midfoot portion and/or the heel portion of the midsole. Thus, the supply of air to the air tube can be conducted with ease. Additionally, integral formation of the cover portion with the outsole can simplify the whole structure of the sole.